Add sysinfo interface definition

src/sysinfo/interface.js

@@ -0,0 +1,20 @@
+'use strict';
+
+// -------------------------------------------
+//  This file just describes the interface
+//
+//  New backends can start from here
+// -------------------------------------------
+
+exports = module.exports = {
+    getIp: getIp
+};
+
+var assert = require('assert');
+
+function getIp(callback) {
+    assert.strictEqual(typeof callback, 'function');
+
+    callback(new Error('not implemented'));
+}
+